644023108 has 24 divisors (see below), whose sum is σ = 1148152320. Its totient is φ = 316021440.

The previous prime is 644023033. The next prime is 644023151. The reversal of 644023108 is 801320446.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 58248 + ... + 68416.

It is an arithmetic number, because the mean of its divisors is an integer number (47839680).

Almost surely, 2^644023108 is an apocalyptic number.

It is an amenable number.

644023108 is a deficient number, since it is larger than the sum of its proper divisors (504129212).

644023108 is a wasteful number, since it uses less digits than its factorization.

644023108 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10467 (or 10465 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 28.

The square root of 644023108 is about 25377.6103681966. The cubic root of 644023108 is about 863.5758395420.

The spelling of 644023108 in words is "six hundred forty-four million, twenty-three thousand, one hundred eight".